Water-free preparation and use thereof as sewing yarn finish

ABSTRACT

The present invention relates to water-free preparations and their use as a sewing yarn finish which comprise (1) 70-98% by weight of a polydialkylsiloxane, (2) 1-29% by weight of a paraffin wax, (3) 0-6% by weight of a fatty acid having 8-22 carbon atoms, (4) 0-6% by weight of a fatty acid ester having 8-22 carbon atoms in the fatty acid radical and 3-22 carbon atoms in the fatty alcohol radical and also (5) 1-5% by weight of a mediator.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. §119 to GermanApplication 101 52 426.9 filed in Germany on 24 Oct. 2001, and as acontinuation application under 35 U.S.C. §120 to PCT/EP02/11865 filed asan International Application on 23 Oct. 2002 designating the U.S., theentire contents of which are hereby incorporated by reference in theirentireties.

BACKGROUND

[0002] A water-free preparation and its use as a sewing yarn finish aredisclosed.

[0003] It is known that sewing yarns are finished with preparationswhich are composed of silicone oils, paraffins and other additives andwhich endow the finished yarn with particular slip and frictionproperties in order that it may withstand the high stresses of thesewing operation.

[0004] There are various causes for the extremely high stress on thesewing yarn. The following parameters are key: the yarn drag (dependenton the braking force set at the sewing machine); the force due to theyarn take-up spring; the frictional forces arising at points ofdeflection; the continual changes in load on the sewing yarn; and alsothe inertial forces which occur in the course of abrupt accelerations.Industrial sewing machines in use today operate at between 6000 and12000 sewing cycles per minute and pull a defined yarn piece through theeyelet of a needle at up to 60 times per cm of seam. This results inextremely high rubbing and scuffing forces, not only due to the contactof the individual fibre of the yarn with sewing machine parts,especially the eyelet of a needle, but also due to the rubbing of theindividual fibres against each other within the fibre assembly duringloop formation.

[0005] Owing to the high sewing speed, various machine parts heat up to400° C. as a result of friction due to the material to be sewn. Thisapplies in particular to the sewing needle on piercing through thematerial to be sewn, to the frictional contact between the metal of thesewing needle and the woven knitted fabric of the substrate to be sewnor else to the take-up lever. The machine parts which are in directcontact with the sewing yarn and heat up to extremely high temperaturesas a result of friction are particularly critical for sewing yarnscomposed of synthetic materials, for example polyamide (PA) orespecially polyester (PES). Their softening range at 210-250° C.according to provenance is so low that sewing needle temperatures ofabove 300° C. lead to incipient melting and hence rupture of the sewingyarn. This applies especially to sewing multiple layers of closely wovenmaterial, such as denim articles (jeans) etc.

[0006] To improve the resistance of the sewing yarn to the stressesdescribed, it is customary to finish the sewing yarn with compositionswhich contain paraffin wax as a surface-smoothing component and alsopolydimethylsiloxanes to reduce the transfer of the heat of frictionfrom the sewing needle to the sewing yarn substrate.

[0007] However, mixtures of the lubricant components paraffin andpolydimethylsiloxane and also any other additions such as, for example,fatty acids and esters and also any antistats are not stable at ambienttemperature, but form heterogeneous, coarsely disperse systems whichtend to separate into plural phases during storage. A continuous,homogeneous phase will customarily only appear at temperatures above themelting point of the hydrocarbonaceous components, i.e. usually above70° C. Consequently, the preparations have to be applied to the sewingyarn at these high temperatures in order that the constant ratio betweenthe individual components of the finish (which is necessary to achieveoptimal sewing results) may be achieved and transferred to the sewingyarn. This prior art method of application is known as “hot melt”.

[0008] EP-A-0340575 describes water-free preparations which are composedof polydimethylsiloxane and a fatty acid or a fatty amine and alsocustomary additives and which constitute clear, homogeneous solutions ata temperature of 45° C. On cooling to ambient temperature, however, thehydrocarbonaceous fractions in the preparations reprecipitate and leadto pasty or waxy products, depending on the composition.

[0009] DE-C-196 15 983 describes water-free preparations consisting of65- 95 parts by weight of polydimethylsiloxane having 350 to 5000 mPa·sat 25° C. and 35 to 5 parts by weight of paraffin which is solid orliquid at ambient temperature and also a compatibilizer consisting of analkyl- or alkoxy-terminated polydimethylsiloxane. The addition of thecompatibilizer is intended to ensure that clear, homogeneous mixturesare formed and that there is none of the customary separation on coolingpreparations composed of silicone oil and paraffin. And indeed: whensuch preparations utilize the silicone oils having viscosities>350 mPa·sthat are necessary for optimal coefficients of friction and sewabilityas well as paraffins having melting points between 40 and 60° C., thecompatibilizer added prevents any separation on cooling of thepreparation. However, the mixture is pasty or creamily solid, dependingon the type of compatibilizer used. Such preparations can therefore onlybe applied from heated galettes or specific applicators.

[0010] To obtain preparations which can be applied also at roomtemperature, EP-A-0474467 utilizes mixtures of polydimethylsiloxane andparaffin wax emulsions in an aqueous phase. Such preparations are liquidat ambient temperature and can be applied to sewing yarn by means of agalette. However, the water content needed to make the product liquidcan cause corrosion on machine parts and also lead to increasedviscosity or drying of the preparation due to evaporation during machineshutdowns when applied from a galette. Moreover, because of the contentof water, subsequent drying of sewing yarn spools is indispensable ifmoulding during storage is to be avoided.

[0011] EP-A-0900876 describes a fibre treatment agent based on adispersion of magnesium soap dispersed in a polydimethylsiloxane ofviscosity range 5-50 mPa·s by means of a dispersant mainly consisting ofa carboxyamide-modified silicone; this carboxyamide-modified siliconehas at least one free carboxyl group which in each case is bonded to thepolysiloxane chain via a carboxamide group. This treatment agent isintended to increase the coefficient of friction between polyurethanefibres.

[0012] All of the foregoing mentioned patent documents are herebyincorporated by reference in their entireties.

SUMMARY

[0013] A water-free preparation is disclosed which is liquid at ambienttemperature and which is suitable for finishing sewing yarn at ambienttemperature or only minimally elevated temperatures. At the same time,the sewing performance properties to be achieved, especially a lowcoefficient of friction and good sewability on the part of the sewingyarn, can be superior to those of the prior art as represented byaqueous finish formulations.

[0014] Surprisingly, this performance profile is achieved by apreparation which, as well as prior art components, includes a mediatorwhich reduces the viscosity of exemplary preparations described hereinto such an extent that application by means of a galette is possible atambient temperature or only insignificantly elevated temperatures.Exemplary preparations do not separate in the process, but remain intactas a homogeneous dispersion depending on the composition chosen. At thesame time, the technological properties of the sewing yarn, such ascoefficient of friction and sewability, can be improved over the priorart.

DETAILED DESCRIPTION

[0015] According to exemplary embodiments of the invention there are nowprovided, in a first aspect, water-free preparations comprising (basedon total composition) (1) 70-98% by weight of a polydialkylsiloxanehaving trimethylsilyl and/or hydroxyl end groups and a viscosity of50-10000 mPa · s, (2)  1-29% by weight of a paraffin wax, (3)  0-6% byweight of a fatty acid having 8-22 carbon atoms, (4)  0-6% by weight ofa fatty acid ester having 8-22 carbon atoms in the fatty acid radicaland 3-22 carbon atoms in the fatty alcohol radical and also (5)  1-5% byweight of a mediator of the formula (I)

[0016]

[0017] or of the formula (II)

[0018] where n and m are integers, n in the formula (I) and the sumtotal of n and m in the formula (II) are between 2 and 50, the ratio ofn:m in the formula (II) is between 1:1 and 49:1 and the radical R₁ is

[0019] where R₃=—H, —CH₃; X=—OR₄ or —NHR₄; the radical R₄=—H, —Na, —K,—NH₄, -alkyl of 2-22 carbon atoms or -phenyl and the radical R₂ in theformula (II) consists of —CH₃ or —OH.

[0020] All the indicated weight figures for exemplary preparationsdisclosed herein are based on the overall composition of the inventivepreparation. Preferred ranges are a range of 75-95, more preferably of90-95% by weight for component (1) and 1-20 but especially 1-10% byweight for component (2). When components (3) and (4) are added, theirconcentration is preferably in the range of 1-6 and especially 1-3% byweight. The concentration of component (5) is in a range of 1-5 andpreferably 1-3% by weight.

[0021] Component (1) consists of polydialkylsiloxane havingtrimethylsilyl and/or hydroxyl end groups which has a viscosity of 50-10000 mPa·s. Preference is given to using linear polydimethylsiloxaneshaving trimethylsilyl and/or hydroxyl end groups. The lateral methylgroups, however, can also be replaced by other organic alkyl or arylgroups. Ethyl and phenyl groups can be contemplated as such, forexample. Component (1) can in unitary form preferably consist ofpolydimethylsiloxane or α,ω-dihydroxy-terminated polydimethylsiloxaneand also of mixtures of the two. The production of polydialkylsiloxanesfor component (1) will be known to one skilled in the art and isdescribed for example by Noll, “Chemie+Technologie der Silicone” p. 162ff. or Houben-Weyl, “Methoden der organischen Chemie” E 20/3 p. 221 ff.

[0022] For preparations to be applied to sewing yarn by means of agalette, they have to have a very low viscosity. It is thereforepreferable to use silicone oils which have ambient temperatureviscosities of 50-10000 mPa·s and especially 1000-5000 mPa·s.

[0023] Component (2) of the preparation consists of a paraffin wax. Thewax can consist of the customary, well-known hydrocarbons from a widerange of provenances. Not only natural waxes, such as beeswax andcarnauba wax, but also synthetic waxes such as polyethylene wax andFischer-Tropsch waxes can be used. However, particular preference is tobe given to linear paraffin waxes with or without a 1-5% by weightfraction of short-chain linear hydrocarbons which are liquid at ambienttemperature.

[0024] Optimal melting points for the paraffins used are known from theprior art. For instance, low-melting paraffins having a melting point<50° C. give distinctly better coefficients of friction than thosehaving melting points >60° C. Particular preference is therefore to begiven to paraffin waxes having a melting range of 40-70° C., butespecially to those having a melting range of 46-58° C.

[0025] Component (3) of the exemplary preparation preferably consists ofaliphatic, unbranched, saturated or unsaturated carboxylic acids. Thecomposition can preferably include fatty acids having 14-20 carbon atomsand particularly having 16-18 carbon atoms in the fatty radical. In thecase of unsaturated fatty acids, they can contain one or more doublebonds in the fatty radical. Embodiments can also utilize plural fattyacids which differ from each other. The production of fatty acids forcomponent (3) will be known to one skilled in the art and is describedfor example in Ullmann's Encyclopaedia of Industrial Chemistry (5thedition) A10, p. 254 ff.

[0026] Component (4) in the exemplary preparation preferably has 10-22carbon atoms but more preferably 14-18 carbon atoms in the acid radical.The fatty acid radical can be linear or branched and can also containone or more double bonds. It may be preferable for the fatty alcoholradical to contain 3-18 carbon atoms, in which case the radical may belinear, but especially branched. The production of fatty acid esters forcomponent (4) will be known to one skilled in the art and is describedfor example in Ullmann (5th) A9, p. 572 ff.

[0027] Component (5) in the exemplary preparation comprises compoundswhich lower the viscosity of exemplary preparations to such an extentthat use is possible at ambient temperature or only insignificantlyelevated temperatures. Ambient temperature is to be understood asmeaning temperatures of 20-45° C. Exemplary preparations do not separateduring their use, but remain intact as homogeneous dispersions,depending on the composition chosen. The production of the mediator forcomponent (5) will be known to one skilled in the art and may be carriedout for example similarly to Examples 1 to 9 of EP-A-0 955 340. Theintegers n in the formula (I) are preferably between 2 and 10, theintegers of the sum total of n and m in the formula (II) are preferablybetween 25 and 50. The ratio of n:m in the formula (II) is preferably ina range of 5:1 and 25:1. The radical R₄ is preferably embodied as analkyl radical having 10-18 carbon atoms.

[0028] As well as the components mentioned, further components can beadded in order that particular effects may be achieved. For instance,small fractions of organic phosphorus compounds and especially oforganic-modified phosphoric esters can improve the electrostaticproperties of finished sewing yarns. When the yarns are to acquire abiostatic or biocidal property, this can be achieved by adding 0.1-0.2%by weight of isothiazolinone derivatives.

[0029] Exemplary advantages of the preparations disclosed herein includefirst in a distinct reduction in the coefficient of friction of sewingyarns finished therewith and secondly in a lowering of the heat offriction due to the sewing operation in the region of the needle eyeletand also of other machine parts in contact with the sewing yarn,distinctly lowering the tendency of a yarn to break during sewing. Afurther advantage resides in the low viscosity of the preparationwhereby application to the sewing yarn is possible by means of a galettewithout the preparation having to be heated to beyond the melting pointof individual components in order that a homogeneous phase may beachieved. However, depending on the type and amount of paraffin used andon the ambient temperature encountered, it can be necessary to minimallyraise the temperature to 35 to 45° C.

[0030] Owing to the significantly lower application temperaturescompared with the conventional “hot melt” process, which is carried outat temperatures between 70 and 90° C., appreciable energy savings can beachieved through partial or complete elimination of the heating for thegalette system. Since, moreover, the exemplary preparation contains noadded water, the disadvantages associated with added water, such ascorrosion of machine parts, increased viscosity for the preparation dueto drying out or mould forming on finished sewing yarns are avoided.Exemplary preparations can at most contain traces of water, which areentrained as impurities with the ingredients used. The amount of anyentrained water is not more than 0.5% by weight and preferably not morethan 0.1% by weight.

[0031] Exemplary preparations are produced by simply mixing thecomponents indicated in the claim together at temperatures above themelting point of the individual components and then cooling to ambienttemperature.

[0032] The invention further provides for the use of inventivepreparations as a sewing yarn finish.

[0033] Preparations disclosed herein are very useful for application tosewing yarns to lower the coefficient of friction and the heat offriction due to the sewing operation in the region of the needle eyeletand of other machine parts in contact with the sewing yarn. The sewingyarns can consist of natural fibres and/or synthetic fibres, especiallyPES and PA fibres. In the case of synthetic yarns, these can have beenproduced not only from staple fibres but also from monofil fibres.Trilobal synthetic yarns can be employed for the specific field ofembroidery yarns. Application is conveniently done from the galettefamiliar to one skilled in the art, in which case exemplary preparationsare fed from a heated or unheated storage vessel by means of pumpsystems via likewise heated or unheated lines to the galette trough.Application can take place at ambient temperature or, if necessary,minimally elevated temperature at 35-45° C., depending on thecomposition of the inventive preparation.

[0034] Add-on levels in the range between 2 and 20% by weight based onsewing yarn weight can be employed for preparations disclosed herein,depending on yarn type and the intended use of the sewing yarn.

[0035] The examples which follow illustrate embodiments of the invention(cf. table hereinbelow). The sewing yarn finish was applied by means ofa laboratory instrument. The viscosity numbers reported in the third rowfrom the end of the table are based on the viscosity of the preparationsused and were determined at 23° C. using a VT 500 viscometer from Haakeof Karlsruhe (SVDIN measuring body). The coefficients of friction weredetermined using an “Anchor Friction Tester” from Kerr & Co.

[0036] Sewability was tested on a Dürkopp 211-5 lockstitch sewingmachine with intermittent drop feed as per the following method:

[0037] Five layers of a plain-woven PAC awning fabric were placed on topof each other in the warp direction and stitched together at one end. Astarting line was drawn at right angles to the warp direction at about 2cm from the stitched end. Strips 10 cm in width (weft direction) and 30cm in length (warp direction) were cut from this fabric and used for anindividual test one at a time. The test fabric was fed loosely duringthe sewing test. The upper thread tension was set to an optimal seamhaving a stitch length of 4 mm. Sewing machine settings were keptconstant during test sewing. Sewing was done at 5000 stitches/min untilthe yarn broke. A new needle was used for each seam in order that theinfluence of deposits on the needle might be eliminated. After the yarnbroke, the length of the stitched seam from the starting line to theyarn breakage point was measured out in cm. Owing to the high measuredvalue scatter, 15 individual seams were produced for each test, with thelowest and the highest value and also unclean seams being excluded fromevaluation. The remaining results were averaged.

[0038] Examples (table): Comp. Inv. Inv. Inv. Inv. Inv. Inv. Inv.Component Untreated example example 1 example 2 example 3 example 4example 5 example 6 example 7 (1) PDMS 90.0 88.0 76.0 76.0 86.0 86.095.0 92.0 1000 mPa · s (2) Paraffin 5.0 5.0 20.0 20.0 10.0 10.0 1.0 6.046/48 (3) Stearic 2.5 2.5 — — — — — 1.0 acid (4) Butyl 2.5 2.5 2.0 2.02.0 2.0 2.0 — stearate (5) Mediator of — 2.0 — — 2.0 — 2.0 1.0 formula(I)¹ (5) Mediator of — — 2.0 — — 2.0 — — formula (I)² (6) Mediator of —— — 2.0 — — — — formula (II)³ Appearance highly viscous, viscous,viscous, viscous, viscous, transparent viscose, viscous liquid dispersedisperse liquid liquid disperse Viscosity [mPa · s] 10000 3000 6000 58001800 1560 900 4000 Coefficient [μ] 0.280 0.196 0.186 0.185 0.198 0.1830.185 0.182 0.190 of friction Sewability Seam 3 10 11 8 7 12 13 13 12test length [cm]

[0039] It will be appreciated by those skilled in the art that thepresent invention can be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Thepresently disclosed embodiments are therefore considered in all respectsto be illustrative and not restricted. The scope of the invention isindicated by the appended claims rather than the foregoing descriptionand all changes that come within the meaning and range and equivalencethereof are intended to be embraced therein.

1. A water-free preparation comprising, based on total composition: (1)70-98% by weight of a polydialkylsiloxane having trimethylsilyl and/orhydroxyl end groups and a viscosity of 50-10 000 mPa · s; (2)  1-29% byweight of a paraffin wax; (3)  0-6% by weight of a fatty acid having8-22 carbon atoms; (4)  0-6% by weight of a fatty acid ester having 8-22carbon atoms in a fatty acid radical and 3-22 carbon atoms in a fattyalcohol radical; and (5)  1-5% by weight of a mediator having a formula:

or a formula (II)

where n and m are integers, n in the formula (I) and a sum total of nand m in the formula (II) are between 2 and 50, a ratio of n:m in theformula (II) is between 1:1 and 49:1 and a radical R₁ is one of

where R₃=—H, —CH₃; X=—OR₄ or —NHR₄; radical R₄=—H, —Na, —K, —NH₄, -alkylof 2-22 carbon atoms or -phenyl, and radical R₂ in the formula (II)consists of —CH₃ or —OH.
 2. Use of a preparation as recited in claim 1as a sewing yarn finish.
 3. A water-free preparation comprising, basedon total composition: (1) 70-98% by weight of a polydialkylsiloxanehaving trimethylsilyl and/or hydroxyl end groups and a viscosity of50-10 000 mPa · s; (2)  1-29% by weight of a paraffin wax; (3)  0-6% byweight of a fatty acid having 8-22 carbon atoms; (4)  0-6% by weight ofa fatty acid ester having 8-22 carbon atoms in a fatty acid radical and3-22 carbon atoms in a fatty alcohol radical; and (5)  1-5% by weight ofa mediator having a formula:

where n is an integer between 2 and 50, and a radical R₁ is one of

where R₃=—H, —CH₃; X=—OR₄ or —NHR₄; and radical R₄=—H, —Na, —K, —NH₄,-alkyl of 2-22 carbon atoms or -phenyl.
 4. A water-free preparationcomprising, based on total composition: (1) 70-98% by weight of apolydialkylsiloxane having trimethylsilyl and/or hydroxyl end groups anda viscosity of 50-10 000 mPa · s; (2)  1-29% by weight of a paraffinwax; (3)  0-6% by weight of a fatty acid having 8-22 carbon atoms; (4) 0-6% by weight of a fatty acid ester having 8-22 carbon atoms in afatty acid radical and 3-22 carbon atoms in a fatty alcohol radical; and(5)  1-5% by weight of a mediator having a formula:

where n and m are integers, and a sum total of n and m is between 2 and50, a ratio of n:m is between 1:1 and 49:1 and a radical R₁ is one of

where R₃=—H, —CH₃; X=—OR₄ or —NHR₄; radical R₄=—H, —Na, —K, —NH₄, -alkylof 2-22 carbon atoms or -phenyl, and radical R₂ consists of —CH₃ or —OH.